This study will be used to validate dynamic PET imaging of 18FDG uptake in muscle for measurement of glucose transport and phosphorylation. Once the technique is validated it will be used to assess glucose transport in the insulin resistance associated with NIDDM and obesity. Results from the PET studies will be related to immunohistochemical studies in which Glut 4 is labeled and identified by quantitative confocal laser microscopy imaging of vastus laterialis muscle obtained by percutaneous biopsy.